This invention relates to an enzymatic decomposition method of chitin-containing materials, and in details supplies the method for decomposing chitin-containing materials efficiently by enzyme reaction.
Chitin is a polysaccharide which exists abundantly in the natural world, and is contained in the shell of the Crustacea such as crabs, shrimps, etc., in the outer frame of insects, and in the cell wall, etc. of a certain molds. Chitin is a long molecule where N-acetylglucosamine is linked by .beta.-1, 4 glycosidic linkage, and the deacetylation of chitin in the highly concentrated thermo-alkali solution yields chitosan. Chitosan demonstrates high adsorption for metal ion and protein, and is utilized as an agglutination agent or as a carrier in bioreactors, etc. The products made from chitin or chitosan have superior compatibility with living bodies and are also used as sutures for physical operation, artificial skins, etc. Further, it is known that polymers or oligomers, decomposed products of chitin and chitosan, have antibacterial and antitumor activities.
Thus, the substance obtained from chitin is highly valued in the industrial application. Since it is difficult to adjust the degree of decomposition in the prior method of acid hydrolysis for decomposing chitin and chitosan, most of the decomposed products are of low molecular weight. On the other hand, the decomposition method utilizing decomposition enzymes such as chitinase, etc. has advantages in that the degree of decomposition can be easily adjusted due to the mild reaction condition and the variable reaction specificity depending on the kind of enzymes, but has the problem that enzymes already known cannot decompose materials efficiently. Therefore, there is a need for the method which can efficiently hydrolize chitin-containing materials and chitosan-containing materials, and makes it possible to control the degree of decomposition.